Notes, summaries, assignments, exams, and problems for Geology

Tunnel Lining Fundamentals

Purpose of Tunnel Lining

• Support tunnel structure.
• Prevent water ingress.
• Improve durability.

Types of Tunnel Lining

• Concrete
• Shotcrete
• Steel
• Masonry

Sections of Tunnel Lining

• Crown: Top of the tunnel.
• Inverts: Bottom of the tunnel.
• Walls: Sides of the tunnel.

Types of Foundation Footings

• Spread Footing (Pad footing) – Supports a single column.
• Strip Footing (Continuous footing) – Continuous foundation beneath a wall.
• Raft Foundation – Covers the entire building footprint; distributes load on weak soils.

Understanding Foundation Settlement

• Definition: Downward movement due to soil compression.
• Notes:
  • Coarse soils: Settlement often ≤ 25 mm (rarely > 50 mm).
  • Loose sands below water table: More settlement.
  • Clay: Consolidation settlement,

1. What are the innermost layers of Earth?

The inner core is the innermost physical layer of the Earth. The core is the innermost chemical layer.

2. What evidence indicates that the outer core is liquid?

Evidence from earthquake waves indicates that the outer core is liquid.

3. How does Earth generate a magnetic field?

It surrounds Earth.

4. Compare the lithosphere and the asthenosphere

The lithosphere is a rigid layer. The asthenosphere is a plastic layer.

5. How is the crust different from the mantle?

The mantle has more iron. The crust is less dense than the mantle.

6. What are the four layers of the mantle?

• Lithosphere
• Asthenosphere
• Uppermost mantle
• Lower mantle

7. Which layer of the mantle has the greatest pressure? Explain

The lower mantle because pressure... Continue reading "Earth's Layers and Systems: Composition and Properties" »

Earth's Fundamental Motions

Two Primary Earth Movements

• Rotation: The spinning of Earth on its axis. Consequences: Day and night cycle, Coriolis effect.
• Revolution: The orbiting of Earth around the Sun. Consequences: Seasons, varying daylight hours.

Earth's Interconnected Spheres

The Four Spheres of Earth

• Atmosphere: The layer of gases surrounding Earth. It provides air for breathing and protects from harmful solar radiation.
• Hydrosphere: All water on Earth, including oceans, rivers, lakes, and glaciers. It plays a key role in the water cycle and supports aquatic life.
• Lithosphere: The rigid outer layer of Earth, consisting of the crust and upper mantle. It forms landmasses and ocean floors.
• Biosphere: All living organisms and their interactions with

1. Earth's Position in Space

   • Earth orbits the Sun at 67,000 mph, maintaining a delicate balance between gravity and velocity.
   • Life exists due to Earth's stable distance from the Sun, allowing liquid water and habitable temperatures.

2. Earth as an Energy and Matter System

   • All changes on Earth result from energy: inputs, storage, transformation, or outputs.

   • Two Primary Energy Sources:

     • Solar Energy: Drives photosynthesis, weather, and food webs.
     • Internal Earth Energy: Causes tectonic activity, earthquakes, and volcanic eruptions.

3. Solar Energy Pathways

   • Photosynthesis: Converts sunlight into chemically bonded energy (food, fossil fuels).
   • Heat Energy: Drives weather systems (e.g., hurricanes, tornadoes).

4. Energy Flow

   • Energy flows into, through, and out of Earth's

Understanding Earth's Dynamic Processes

Earthquakes and volcanic eruptions are fundamental geological events caused by movements within the Earth's lithosphere, specifically the interaction of tectonic plates.

The Earth's Moving Plates

The Earth's outer layer is composed of large sections called plates. These plates consist of two primary types of crust:

• Continental Crust: This type of crust is generally older, lighter, and does not readily sink back into the mantle. It is considered permanent.
• Oceanic Crust: In contrast, oceanic crust is younger, heavier, and can sink (subduct) into the mantle. It is constantly being destroyed and replaced through geological processes.

Plate Margins: Where Plates Interact

The boundaries where two plates meet are... Continue reading "Earth's Dynamic Plates: Earthquakes, Volcanoes, and Landforms" »

Brief Definition

Global warming refers to the gradual increase of the earth's average surface temperature, due to excessive greenhouse gases in the atmosphere.

Possible Solutions

While this may seem like a small change, we can avoid the consequences by being aware of the problem generated by the gases or other chemicals that we use every day in our lives. This could reduce GHG emissions.

Main Factors

• The build up of the gases in the atmosphere.
• Burning of fossil fuels like coal and oil.

My Opinion

I think we need to have control of what we do or use. We must have a lot of information on the subject and contribute with our small but essential grain of sand.

Volcanic Eruptions

Molten rock and gases are ejected through the Earth's crust.

Continental Drift

A slow horizontal movement of the continents.

Earthquakes

A violent trembling of the Earth's crust which lasts a short time and varies in intensity.

Isostasy

Slow vertical movement of the Earth's crust.

Our atmosphere was formed about 4,000 million years ago.

The Magnetic Field

Around the Earth originates in the outer core.

Hot Rocks

Allow the installation of geothermal plants that take advantage of the heat to vaporize water and produce electricity.

Hydrothermal Phenomena

Occur when water seeps into the crust through cracks, it gets into contact with rocks at high temperatures.

The Earth's crust is a rigid and cold layer. Magma is a mixture of gases and molten... Continue reading "Earth's Geology and Natural Phenomena" »

Diphthongs

Described as vowel glides, since in their production the tongue begins in one place and moves to another. This movement of the tongue, however smooth, results in a change of vowel quality, which is why diphthongs are sometimes looked upon as 'combinations of 2 vowels'.

Diphthongs are usually classified according to whether they are:

• Falling or rising
• Wide or narrow
• Front or back
• Closing or centering

The diphthongs of RP are all stressed on the first element, described as falling. Those stressed on the finishing point (rising), can also be wide or narrow, according to the movement of the tongue from the first to the second target. Those in which the position of the tongue body changes quite noticeably are described as 'wide diphthongs'.... Continue reading "English Phonetics: Diphthongs and Consonants" »

Just 2.5% of water on Earth is fresh water. About 69% of that fresh water is frozen. This means that less than 1% of water on Earth is drinkable.

1. The Atmosphere

1. The atmosphere

Earth's gaseous atmosphere is mostly nitrogen & oxygen. It also contains argon, carbon dioxide, ozone & water vapor.

Earth's atmosphere has an upper limit of 10,000 kilometers.

Most of the gases are found in the lowest 15 kilometers.

ATMOSPHERIC PRESSURE

The gases in the atmosphere push down on Earth's surface.

The weight of all these gases is called atmospheric pressure.

We measure atmospheric pressure in standard units called pascals. 1 standard atmosphere = 101.325 pascals.

There is more pressure at lower altitudes, near Earth's surface. There is less pressure at... Continue reading "Earth's Fluid Spheres: Atmosphere and Hydrosphere" »

What is an Environmentally Sustainable Society?

One that meets the current and future basic resource needs of its people in

a just and equitable manner without compromising the ability of the future

generations to meet their basic resource needs

Environmental Scientists

John Muir (1892) - created Yosemite National Parks

Created Sierra club

Eugene and Howard (1953) - wrote the first ecology textbook

Rachel Carson (1962) - wrote Silent Spring

Effects of DDT

Lois Gibbs (1980) - formed the Citizens Clearinghouse for hazardous

 waste, petition to Jimmy Carter

The town was called Love Canal

Theodore Roosevelt (1900) - created the United States Forest Service

 for Wildlife

Established 5 national parks

Antiquities Act

James Lovelock (1960s) - created the Gaia